A = √8−2√7 - √8+2√7

----- Nội dung ảnh -----
8) \( A = \sqrt{8 - 2\sqrt{7}} - \sqrt{8 + 2\sqrt{7}} \)

10) \( A = \sqrt{28 + 10\sqrt{3}} + \sqrt{19 - 8\sqrt{3}} \)